Curtis Mayfield, who died Sunday at age 57, changed the character of soul music.

It began with "Keep On Pushing," one of the first pop songs embraced by the civil rights movement. The song, released shortly before passage of the historic Civil Rights Act of 1964, became a favorite of the Rev. Martin Luther King Jr., who recognized its challenge to African Americans to strive for justice and equality:

"Now maybe someday I'll reach that higher goal/ I know I can make it with just a little bit of soul/ 'Cause I've got my strength and it don't make sense/ Not to keep on pushing."

Pushing is what Curtis Mayfield did. His cool-as-ice tenor and falsetto vocals graced a string of hits that preached an empowering gospel of black pride, unity and self-determination.

As Gladys Knight once put it: "Even though we as a people didn't know where we were going, Curtis led the way."

Even before "Keep On Pushing," there was the jubilant "It's All Right," which counseled, "You've got soul/ And everybody knows/ That it's all right." After "Pushing," there was the stately "People Get Ready," with its gospel-style message of anticipated justice. "People get ready, 'cause there's a train a-coming/ And all you need is faith to hear the diesels humming/ . . . Don't need no ticket/ You just thank the Lord."

And the spirited "We're a Winner," released eight months before James Brown's "Say It Loud (I'm Black and I'm Proud)," shared a message of self-respect: "We're a winner and never let anybody say you can't make it/ . . . We don't need no luck, we're movin' on up."

There were other anthems, as well: "Choice of Colors," "Check Out Your Mind," "We People Who Are Darker Than Blue" and "This Is My Country": "Some people think we don't have the right to say this is my country/ I paid 300 years or more of slave driving sweat and welts on my back/ This is my country."

Mayfield wasn't consumed by social revolution alone, of course. He also wrote romantic classics such as "Gypsy Woman," "Woman's Got Soul," "Fool for You" and "Finally Got Myself Together."

At the end of his career, soul music's gentle giant faced personal tragedy. During a 1990 performance in Brooklyn, a lighting rig fell on him during a freak windstorm and broke his neck, leaving him permanently paralyzed from the neck down.

Although he was quadriplegic, Curtis Mayfield's spirit was strong. On a 1994 tribute album, he was able to sing a verse of his 1975 chart-topper for the Staple Singers, "Let's Do It Again." And two years later, Mayfield did do it again with his 25th album, "New World Order." He recorded it strapped upside down to a bed so he could use the natural force of his own weight on his chest and lungs to bring more power into the vocals.

On one track, "Back to Living Again," Mayfield tapped one last time into the nurturing spirit of his music: "Now is always the right time/ With something positive in your mind/ There's always someone to pull you down/ You just get back up and hold your ground."

There was always a higher ground in Curtis Mayfield's music. His roots, like those of so many early R&B and soul pioneers, were in gospel. "Keep On Pushing" itself was a gospel song adapted to the secular market.

Mayfield, however, was an original, not a copier. He was a singer-songwriter-performer when that was not the norm in black popular music. As a producer, his smooth Chicago soul provided friendly rivalry to Detroit's Motown, Memphis's Stax and the Philly sound. And along with Sam Cooke, he was one of the few black artists to take control of publishing their music early in their career. He was also one of the first to own a label (Curtom, which released most of Mayfield's later albums). As a musician, he was, as Jerry Butler once noted, "as important to R&B guitar as Wes Montgomery is to jazz guitar."

Born in Chicago, Mayfield first performed in a gospel group with his cousins, the Northern Jubilees. A self-taught guitarist, he developed a distinctive style featuring brittle brush chords colored by an open tuning he favored. Mayfield soon met another North Side teenager, Jerry Butler, and in 1956 they formed the Impressions. A year later the group scored its first hit with the lush ballad "For Your Precious Love," but broke up soon afterward when their label credited the single to Jerry Butler & the Impressions, and then decided to push Butler as a solo artist.

Butler, an alderman in the Chicago City Council since 1986, went on to a successful solo career, thanks to such Mayfield-penned hits as "He Will Break Your Heart" and "Find Another Girl." Mayfield led Butler's backing band for a couple of years and saved enough money to re-form with the other Impressions, and they had a string of hits beginning with "Gypsy Woman" in 1961.

It was with the Impressions that Mayfield began to craft music with a social message. Surprisingly, that was new for soul music, which in the first decade of the civil rights movement mostly avoided advocacy and commentary. There were notable exceptions--Sam Cooke's 1965 classic "A Change Is Gonna Come," for instance--but broadsides demanding social and political equality weren't prevalent until the rise of the black power movement in the late '60s.

Mayfield's approach was for the most part moderate, more positive than confrontational. As Michael Rodrigues noted in Vibe a few years ago, the passion and frustration of Mayfield's art "fit perfectly into the mosaic that was America in the '60s and '70s--beautiful, angry, scared, happy and hopeful blackness poured out of his mouth and his musical instrument."

"Our purpose is to educate as well as to entertain," Mayfield told Soul magazine in 1969. " 'Painless preaching' is as good a term as any for what we do. If you're going to come away from a party singing the lyrics of a song, it is better that you sing of self-pride like 'We're a Winner' instead of 'Do the Boogaloo.' "

Mayfield left the Impressions the following year to embark on a solo career. In 1972 he created the classic funk soundtrack for "Superfly," whose stark portraits of a ghetto subculture of drugs and violence presaged rap's harsh imagery and themes. Long before anyone could argue about "keeping it real," Curtis Mayfield made it real. In the current issue of the hip-hop journal XXL, which features an overview of Mayfield's 40-year career, Jerry Butler puts it succinctly: "Curtis stopped talking about make-believe and started talking about reality."

Though "Superfly" is generally regarded as Mayfield's most accomplished solo achievement, he also created compelling scores for "Claudine" and "Sparkle" (for Gladys Knight and Aretha Franklin, respectively). "Superfly" would also be Mayfield's last major achievement. Though he had three Top 10 R&B hits in the mid-'70s with slight material like "Kung Fu," "So in Love" and "Only You Babe," Mayfield had only one Top 20 R&B hit through the '80s.

Tragically, it was Mayfield's accident that sparked recognition of just how important he had been. That realization resulted in two star-studded tribute albums ("All Men Are Brothers" and "People Get Ready") and several elegant retrospectives (the best are MCA's "The Anthology 1961-1977" and Rhino's "The Curtis Mayfield Story").

A few years ago, Rolling Stone made a list of 200 essential albums, including the MCA anthology. Without Curtis Mayfield, it said, "black music as we hear it today simply wouldn't exist."

In that collection, author Robert Pruter wrote that Mayfield "sang deeply humanistic songs that represented the highest aspirations of African Americans, evoking their pain, struggle and fortitude, and preached that with goodwill, love, pride and self-achievement they could find a respected role in American society."

Curtis Mayfield's respected role in the history of popular music was a reflection of his ambition and compassion. American music simply wouldn't sound as good or be as meaningful without him.

CAPTION: With his socially conscious songs, Curtis Mayfield, shown performing in 1974, brought deeper meaning to R&B music.

CAPTION: Mayfield's music for "Superfly" explored ghetto life and influenced themes in rap.